Converting a Garage Into a Guest Room

Does anybody have any thrifty ideas for changing a garage temporarily into a guest bedroom? It's not that cold where we live and basically all the heat we lose would be through the garage door. Does anyone know of any way to insulate the garage door and still allow it to open if needed?

A cheap suggestion for insulation the garage door would be to put up a curtain rod or string across in front of it, (of course allowing for working room) and then put up some heavy curtains (drapes) or even quilts/ bedspreads etc. This will block off the door insulating the room but will also allow for privacy when the door is open.

To insulate a steel garage door, buy the rolls of insulation at your local home store. Unroll and cut to fit across the length of the door placing the paper side towards you. The insulation will fit into the "grooves" on the back (or inside) of the steel door. My dad did this and put wire across the insulation every so often to hold it in. His door still opens because the insulation is approximately the same width as the inside section of the door once the wire is put in. You could probably also use twine or string in place of the wire.